Pact for Caller only if you have a cradle, because you usually need elves to pay for pact...
3-4 wish + bojuka bog should be good enough answer for dredge...
What I like about the build with the 4 titania is that it abuses this card a lot for mana acceleration. Not sure if sacrificing 1 card (spirit guide) is worth it for playing titania in T1... But the basic gameplan to get titania/archdruid out and have tons of mana next turn with 7-8 untap effects + 4 glimpse, and with GSZ, Pact + regal overall 11 cards to go off...
The good thing of having 2 GSZ is that it also give access to protection (zealot)... I am thinking about a similar build with additional protection using eternal witness.
I like GSZ more than Genesis wave because if I have 8+ mana in T3 i rather GSZ for regal to go off the same turn instead of casting a wave for x = 5.
Probably going to Goldfish and playtest this one:
Creatures
3 Elvish Archdruid
3 Priest of Titania
3 Elvish Visionary
4 Heritage Druid
4 Llanowar Elves
4 Nettle Sentinel
4 Quirion Ranger
1 Regal Force
1 Viridian Zealot
4 Wirewood Symbiote
1 Eternal Witness
2 Fyndhorn Elves
1 Joraga Warcaller
Instants
4 Summoner's Pact
Legendary Creatures
1 Emrakul, the Aeons Torn
Sorceries
4 Glimpse of Nature
2 Green Sun's Zenith
Basic Lands
5 Forest
4 Misty Rainforest
4 Verdant Catacombs
Legendary Lands
1 Gaea's Cradle
SB
1 Viridian Zealot
2 Krosan Grip
4 Natural Order
1 Progenitus
3 Null Rod
2 Choke
2 Fecundity